A Guide to the Adult Damselflies

8/4/2019 A Guide to the Adult Damselflies

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A Guide to the Adult Damselflies & Dragonflies of the OttawaDistrict

List of Species and their Preferred Habitats

There are many words used in English to describe bodies of water. The meanings of many overlapconsiderably in common usage. I use the following definitions in this guide, which concentrate on thefeatures important to dragonflies:

water volume mostly free of vegetation:

o ditch: narrow (less than 5 meters wide), shallow (less than a meter deep), long, no visible current (includes man-

made, and beaver/muskrat trails)

o stream: a ditch with perceptible to moderate current, but no white water

o river: a stream more than 5 m wide, much more than a meter deep, some current

o rapids: white water (at least during spring runoff)

o outlet: where a stream empties into a lake

o puddle: shallow (much less than a meter), small ( a few meters or less across), no current

o pond: moderate depth (1-5 m), moderate size (1 ha or less), no current

o pool: a deep portion of a stream, with some eddy current

o lake: large (greater than 1 ha), at least some deep portions (more than 5 m), no current

o large: (lake or river) large enough to have breaking waves and wind-driven current

o calcareous: limestone region, pH >7.5

water heavily vegetated:

o bog: most water volume filled with plant material such as sphagnum, pH less than 6

o marsh: heavily-vegetated (typically cattails) pond or lake edge, pH 6 or greater

Species noted as southern(S) can be expected only in the warmer portions of the district, northern(N) onlyin cold bogs. Species that are exceptionally local(L) in distribution or rare(R) here are noted as well.Excepting these species, habitats mentioned are those in which the species is most likely to be found here,and are not to be treated as the only places to look. Species in brackets are known only from close to thedistrict, not from within it.

Zygoptera

Calopteryx maculata small forest streams

Calopteryx aequabile larger wooded streamsL Lestes eurinus small lakes, ponds

Lestes congener temporary/permanent ponds

S Lestes inaequalis marshy ponds, slow streams

Lestes unguiculatus temporary ponds, overwinter as eggs

Lestes vigilax marsh/bog-margined lakes

S Lestes rectangularis partly shaded ponds

Lestes dryas temporary/permanent ponds

Lestes forcipatus temporary/permanent ponds, weedy streams

Lestes disjunctus ponds, weedy streams

L Amphiagrion saucium small, spring-fed bogs at hill bases

Chromagrion conditum shady spring-fed brooks, pools

Nehalinnia irene still marshes, bogs

L Nehalinnia gracilis sphagnum bogs

Argia moesta rocky shores or streams, lakes

Argia fumipennis small shallow rocky streams

Ischnura verticalis any still water

Ischnura posita shaded spring-fed streams, ponds

Coenagrion resolutum still shaded water

(RL Coenagrion interrogatum quaking bogs)

Enallagma ebrium limestone marshy ponds, streams

N Enallagma boreale cold bogs

Enallagma hageni acid marshy/boggy ponds


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N Enallagma cyathigerum very cold bogs

Enallagma carunculatum lakes, rivers

S Enallagma civile ponds, slow streams

S Enallagma geminatum small lakes, slow streams

Enallagma exsulans streams, lake shores

R Enallagma antennatum clayey quiet streams, small lakes

S Enallagma vesperum marsh-bordered lakes, slow streams

Enallagma signatum slow streams, quiet bays

Anisoptera:Anax junius migratory, still water with emergent vegetation, esp.sand pits

Basiaeschna janata small woodland streams with gentle current and their outlets

R Nasiaeschna pentacantha slow woodland streams, small lakes

S Epiaeschna heros shady ponds at wood edges

Boyeria grafiana fly until well after dusk, rock- margined lakes and streams

Boyeria vinosa fly until well after dusk, shady streams with gentle rapids

Aeshna umbrosa shady wooded ditches and streams

Aeshna constricta open marshes and ponds with emergent vegetation

(N Aeshna sitchensis puddles in almost filled cold bogs)

Aeshna interrupta shallow marshy or boggy lakes

S Aeshna clepsydra shallow marsh-bordered lakes

Aeshna eremita marsh-bordered lakes, sand pit ponds(N Aeshna subarctica puddles in cold sphagnum bogs)

(N Aeshna juncea peaty puddles and ditches, shallow lakes)

Aeshna tuberculifera ponds, especially in bogs

Aeshna canadensis still marshes on lake edges, slow streams

LS Aeshna verticalis spring ponds, marsh-bordered lakes

Hagenius brevistylus slow rocky forest streams and their outlets

N Stylogomphus albistylus small rapid gravel streams

Dromogomphus spinosus rapid streams, rivers, lakes

N Ophiogomphus colubrinus rapid gravel streams

L Ophiogomphus anomalus wide rivers, rapid streams

Ophiogomphus rupinsulensis streams and rivers

Ophiogomphus aspersus cold clear rapid streams

RN Ophiogomphus mainensis clear running streams

R Gomphus lividus sheltered inlets on wavy lakes, gentle streams

Gomphus exilis quiet soft-bottomed streams and lake borders

Gomphus spicatus still marshy waters

S Arigomphus furcifer marshy ponds and lakes

SL Arigomphus cornutus small marshy lakes

L Gomphus descriptus rapid streams with pools

R Gomphus borealis lakes, slow streams, sand pit ponds

Gomphus fraternus turbulent water, calcareous

R Gomphus ventricosus rivers

Gomphus vastus large rivers, lakesGomphus adelphus clear running streams, exposed lake shores

R Stylurus amnicola rapid streams, wide rivers

N Stylurus scudderi cold gravelly forest streams and rivers with rapids

Stylurus notatus wide rivers

L Stylurus spiniceps wide rivers

L Cordulegaster obliqua tiny shaded rapid streams in deciduous woods

Cordulegaster diastatops streams with rapids in spring, pools in clearings

Cordulegaster maculata rapid streams in forests

Didymops transversa slow forest streams, wavy lakes

Macromia illinoiensis fast streams, exposed wavy lakes and wide rivers


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L Nannothemis bella puddles and ponds in floating sphagnum bogs

(S Pachydiplax longipennis lakes, ponds, slow streams)

RS Pantala hymenea small standing water esp.sand pits

S Pantala flavescens small standing water esp.sand pits, migrant

Erythemis simplicicollis clear ponds, lake borders

S Celithemis eponina ponds, lakes and slow streams

LS Celithemis elisa marshy lakes and ponds

Libellula luctuosa ponds, small lakes and marshes

Libellula julia bog ponds to swampy lakes

Libellula lydia puddles to ponds

Libellula pulchella sunny ponds, lake borders, calcareous

Libellula quadrimaculata still water

Libellula incesta ponds, slow streams

Leucorrhinia glacialis bog lakes and marshes

(N Leucorrhinia patricia puddles in peat bogs)

Leucorrhinia hudsonica puddles in cold marshes and bogs

N Leucorrhinia frigida floating bog lakes, marshy ponds

Leucorrhinia proxima still marshes

Leucorrhinia intacta slow streams, marshy bays, farm ponds

Sympetrum internum slow shady streams, ponds

R Sympetrum rubicundulum still water

Sympetrum obtrusum tiny, even temporary, ponds in wet meadows and gravel pits

R Sympetrum semicinctum spring-fed ponds, marshes

Sympetrum danae peaty marshes, bog ponds

Sympetrum vicinum slow streams, permanent ponds

Sympetrum costiferum sand or gravel pit ponds

Neurocordulia yamaskanensis wave-washed rocky shores of rivers and lakes, rapids, flies only briefly after dusk

RN Williamsonia fletcheri puddles in sphagnum bogs

Epicordulia princeps quiet small lakes, rivers

Helocordulia uhleri edges of rapid streams and their outletsDorocordulia libera bog ponds, sluggish marshy streams

Cordulia shurtleffi quiet marshes, boggy ponds

Tetragoneuria spinigera marshy non-stagnant borders of lakes and streams

Tetragoneuria canis acid ponds and streams

Tetragoneuria cynosura marsh-bordered lakes and slow streams

Somatochlora tenebrosa tiny shaded deciduous forest streams

(N Somatochlora cingulata lakes)

N Somatochlora albicincta boggy places with slight water movement

N Somatochlora franklini puddles in spring-fed bogs

Somatochlora minor clear slow forest streams

Somatochlora walshi small ditches in bogs

Somatochlora forcipata tiny boggy spring-fed streams, puddles in bogs

(N Somatochlora elongata forest streams with rapids and their outlets)

Somatochlora williamsoni quiet shady forest streams and their outlets

N Somatochlora kennedyi cold bog ponds and puddles

(N Somatochlora incurvata sphagnum ponds and puddles)

Identification Drawings


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Side view(Note that no single dragonfly has all the features as shown. They were selected for

clarity from several genera.)

Front wing (Libelluloidea)

Hind wing


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A Guide to the Adult Damselflies & Dragonflies of the OttawaDistrict

Key to Species

Most of this key is reduced from published works that include many more species than occur in the OttawaDistrict, primarily from E.M.Walker, 'The Odonata of Canada and Alaska'. I also consulted in detail

J.G.Needham & M.J.Westfall, 'A Manual of the Dragonflies of North America'; A.Robert, 'Les libellules du

Qubec'; and R.Hutchinson & A.Larochelle, 'Manuel d'identification des Libellules du Qubec'. In thereduction, I favoured terms that are visible on a living insect. Each term of the key was verified using allapplicable specimens in the Canadian National Collection of Insects (Ontario & Quebec, excluding the farnorth). The field-mark oriented sections marked by symbols are my own, are based solely upon livinginsects within the Ottawa District, and appear only in cases where I am certain that they are significantlymore reliable in the field here than the specimen-based key.1 fore and hind wings similar; eyes separated by more than their own width Zygoptera 2

hind wing broader than forewing Anisoptera 11

2 Zygoptera: damselfiles

wings not stalked at base, many crossveins before nodus Calopteryx 3

wings stalked at base, two crossveins before nodus 2a

2a wings held spread open when resting; vein M3 rises from M1-2 closer to arculus than to nodus Lestes 4

wings held together above back when resting; M3 rises behind nodus Coenagrionidae 5

3 Calopteryx: unstalked broad wings held together above back when resting

male: wing all clear, female: wing diffuse colour to beyond nodus, end clear; 3Jun-2Sep C.aequabile

male: wing all dark, female: wing all smoky with white spot at stigma; 27May-10Sep C.maculata

4 Lestes male

lower appendages much less than half the length of upper; thorax dark metallic green, wings

yellowish 27May-28Jun

Lestes eurinus

lower appendages half or a bit less the length of upper; thorax nearly black 9Aug-13Oct L.congener

lower appendages longer than upper, ends curved in; metallic green 30May-8Aug L.inaequalis

lower appendages S-curved with divergent ends; blue eyes yellow lower lip black thorax 8Jun-9Sep L.unguiculatus

upper appendages meeting at acute angle; dark metallic green 16Jun-27Aug L.vigilax

abdomen very long and slender; hairy green lower lip, 15Jun- 10Sep L.rectangularis

thorax metallic green above yellow sides; stout, 30May-25Aug L.dryassegment 2 3/5 as long as 3, rear tooth of upper appendages blunt, much smaller than front one;

blackish, greenish face 6Jun- 21SepL.forcipatus

segment 2 1/2 as long as 3, rear tooth of upper appendages acute, as large as front one; blackish,

greenish face 2Jul-21Sep

L.disjunctus

4a Lestes: female

ovipositor 1/2 or less as long as segment 7 4b

ovipositor as long as segment 7 4c

wing yellowish L.eurinus

thorax dark brown, narrow pale yellow stripe L.congener

dark areas of abdomen bronzy colour L.disjunctus

these areas greenish L.unguiculatus

4b grey humeral stripe more than 1/2 as wide as dark brown stripe above; fewer than 14 postnodalcrossveins

L.rectangularis

reddish-brown humeral stripe 1/3 or more thickness of metallic stripe above L.vigilax

this stripe yellowish, less than 1/4 thickness of stripe above L.inaequalis

4c thorax metallic green, stripe clear yellow L.dryas

thorax dull bronze-brown, stripe pale yellow L.forcipatus

5 Coenagrionidae:

leg hairs twice as long as the space between them Argia 6

leg hairs only a bit longer than the space between them 5a

5a two spots on top back of head next to eye 5b

no such spots 5d
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5b M2 arises near the 4th crossvein after the nodus in forewing, between 2nd & 3rd vein in hindwing Ischnura 7

M2 arises near the 5th crossvein after the nodus in forewing, near the 4th vein in hindwing 5c

5c male: lower appendages with notch when viewed from side, female: segment 8 without spine on

bottom

Coenagrion 8

male: lower appendages triangular when viewed from side, female: segment 8 with spine on bottom

rear

Enallagma 9

5d body only red and black; small 1Jun-8Aug Amphiagrion saucium

body blue & black with bright sulphur yellow stripe on thorax rear; 7Jun-4Aug Chromagrion conditum

thorax metallic green top blue bottom, abdomen blue (male) blue-green (female) with black areas

all the way to segment 10; 1Jun-28Aug

Nehalinnia irene

as N.irene but no black on segments 9 or 10; 30May-12Aug N.gracilis

6 Argia: argos = bright (coloured)

upper parts of segments 3-6 black-brown; 7Jun-12Sep Argia moesta

violet-blue; 19Jun-19Aug A.fumipennis

7 Ischnura: ischnos = thin, oura = tail

two narrow long shoulder stripes; 5May-15Oct Ischnura verticalis

two exclamation marks on shoulder; 4Jun-9Sep I.posita

8 Coenagrion: agrios = field

two long shoulder stripes; 12Jun-29Jul Coenagrion resolutum

two wide exclamation marks on shoulder; (Muskoka 3Jun-25Jul) C.interrogatum

illustrations for 1-89 Enallagma male: enallex = crosswise (striped)

black of segments 3-4 less than 2/3 length of segment; pale blue 9a

this black more than 4/5 length of segment 9c

9a upper appendages longer than lower, a pale bump on upper end 9b

upper appendages clearly split in two; 30May-24Aug Enallagma ebrium

upper appendages short and rounded; 16May-24Jul E.boreale

upper appendages slender with points curved up; 30May-21Aug E.hageni

upper appendages with prominent tooth/ridge; 29May-27Jun E.cyathigerum

9b upper appendages symmetrical viewed from side; 18May-20Sep E.carunculatum

upper appendages asymmetrical; 6Jun-12Sep E.civile

9c upper appendages tapered to slender upturned points; 15Jun-3Sep E.geminatum

upper appendages split in profile 9dotherwise 9e

9d upper branch of upper appendages shorter than lower branch; 7Jun-19Sep E.exsulans

both these branches about equal; 9Jun-14Aug E.antennatum

9e upper appendages' height greater than 1/2 their length; 18Jun-29Aug E.vesperum

otherwise; 3Jun-9Sep E.signatum

10 Enallagma female (these are reliably separable only by microscopic examination of thorax plate)

segment 8 with pair of large blue spots E.geminatum

segments 8-10 entirely black above E.hageni or E.ebrium

segments 7,8,9 with similar marking E.civile or E.carunculatum

segment 8 entirely black, 9 or 10 not; eye spots elongated to or almost to occiput 10b

segment 8 black only on rear half or all pale 10a

10a fine line between spots of segment 8 E.boreale

these spots separated by a line at front, a wider gap at rear, side spots reach top of segment 10 E.cyathigerum

10b black humeral stripe twice or more width of pale stripe above 10c

black stripe about same width or narrower 10d

10c black stripe divided by pale line E.exsulans

not so divided E.antennatum

10d pale stripe with gap in middle; M2 begins between crossveins 4- 5 E.vesperum

no such gap; M2 begins between crossveins 5-6 E.signatum

11 Anisoptera:

eyes separated by about half their width Gomphidae 17

eyes touching on top of head or separated by only a tiny fraction of their width 11a
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11a triangles about equally distant from arculus in both wings, both oriented lengthwise on wing Aeshnoidea 12

triangle at least twice as far from arculus in forewing as in hindwing, forewing triangle orientedacross wing, hindwing lengthwise

Libelluloidea 22

illustrations for 9-11

12 Aeshnoidea:

eyes barely touch at top or slightly separated Cordulegaster 21

eyes meet in seam at least height of occiput Aeshnidae 13

13 Aeshnidae:

medial space with more than 1 crossvein; 2 rounded pale spots on thorax sides, yellow stigma Boyeria 14

with one crossvein or none 13a

13a sectors of arculus arising from its upper end, thorax uniform green; 21Apr-15Oct Anax junius

sectors of arculus arising near its middle, thorax brown 13b

13b Rs vein not forked; 3 or more cubito-anal cross veins, blue body with bright yellow strips on thorax

sides 8Jun-17Jul

Basiaeschna janata

stalk of Rs vein with symmetrical fork 13c

stalk of Rs vein up-arched and fork askew forward Aeshna 15

13c radial planate subtends 1 row of cells; very prominent blue frons, face yellowish margined with

brown 20Jun-16Jul

Nasiaeschna pentacantha

subtends more than 1 row at least basal half; largest Odonata here, brown & green, 7Jun-9Sep Epiaeschna heros

14 Boyeria: fly until well after dusk

wing base completely clear; side spots of thorax grey-bluish, segments 9 & 10 similar in colour,body grey-brown 27Jun- 7Oct Boyeria grafiana

wings with brown spots at base (usually small); 2 clear yellowish thorax side spots, segment 10 more

yellow than 9, body brown, 5Jul-22Sep

B.vinosa

15 Aeshna, male:

anal triangle with 3 cells; 2 yellow to green stripes on thorax 15a

with 2 cells 15b

15a rear of head marked with yellow or brown, row of pale spots each side of segments 4-6; some green

on segments 5-10, 12Jun-21Oct

Aeshna umbrosa

rear of head black, no such spots; 19Jul-11Oct A.constricta

15b central thorax stripe 1 mm or less wide and bent in sharp Z; eye seam little if any longer than

occiput, greenish face, T-spot with crescent base (Tremblant 21Jun-14Sep)

A.sitchensis

central stripe not bent sharply, more than 1 mm wide; eye seam at least 2x length of occiput 15c

15c central and lower thorax stripes interrupted, reduced to two elongate spots or absent; yellow head,

dark body 2Jul-1Oct

A.interrupta

these stripes wider, generally full length 15d

15d face with fine but clear black-grey stripe on face suture 15e

stripe not clear, more like a shadow than a marking; upper side of upper appendages hairy 15f

15e large pale spots between green side stripes of thorax, sometimes confluent with central stripe; 5

paranal cells, slender 19Jul-12Sep

A.clepsydra

spotted with blue; 4-5 paranal cells 19Jun-15Sep A.eremita

central thorax stripe clearly concave on front edge; 3-4 paranal cells 12Jul-10Sep A.subarctica

central thorax stripe convex on leading edge (may be only slightly); 3-4 paranal cells 14Jul-31Aug A.juncea

15f segment 10 all black; large thorax stripes 27Jul-22Sep A.tuberculifera

pale spots on dorsum of segment 10 15g

15g central thorax stripe mostly or all blue; 21Jun-27Sep A.canadensis

this stripe all green; 14Jul-11Aug A.verticalis

16 female:

central thorax stripe 1 mm or less wide and bent in sharp Z; eye seam little if any longer than

occiput, greenish face, T-spot with crescent base

A.sitchensis

central stripe not bent sharply, more than 1 mm wide; eye seam at least 2x length of occiput 16a

16a palp of ovipositor (see 4a) as long as segment 10 16b

palp much shorter than segment 10 16c

16b front edge of central thorax stripe nearly straight; thin pencil of hairs at end of vulva A.tuberculifera

this edge distinctly sinuate; no such pencil of hairs A.constricta

16c face with black line on face suture 16d
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any such line indistinct 16f

16d central and rear thorax stripes interrupted, reduced to two elongate spots or absent A.interrupta

these stripes well developed 16e

16e front thorax suture with large triangular pale spot below A.clepsydra

4-5 paranal cells; spotted with green 19Jun-15Sep A.eremita

central thorax stripe concave on front edge; 3-4 paranal cells A.subarctica

central thorax stripe convex on leading edge; 3-4 paranal cells A.juncea

16f central thorax stripe straight, margined with blackish A.umbrosa

central stripe distinctly sinuate 16g16g central thorax stripe mostly or all blue A.canadensis

this stripe all green A.verticalis


17 Gomphidae:

triangles with a cross vein, each with a supplementary longitudinal vein springing from its outeredge; very large, small head, black and greenish yellow, eats other dragonflies 21Jun-21Aug

Hagenius brevistylus

triangles clear, no such vein, rarely 65 mm long 17a

17a male: hind wings with anal loop, usually 3 cells, lower appendage ends separated slightly, female:

vulva nearly as long as the rear of segment 9

Ophiogomphus 18

male: without anal loop, lower appendage ends widely separated, generally divergent, female: vulva

usually less than half as long as the rear of segment 9

17b

17b small, 25-40 mm long, stigma less than 4x as long as wide and more than 2x as wide as the spacebehind its middle; greenish with lots of black 21Jun-14Aug Stylogomphus albistylus

42-65 mm long, stigma rarely less than 4x as long as wide, less than 2x as wide as this space 17c

17c long hind legs reaching the base of segment 3 with 4-7 long spines below; dark brown, distinctive

pale green markings on thorax 5Jun-31Aug

Dromogomphus spinosus

hind legs not reaching beyond the middle of segment 2, only short spines Gomphus 20

18 Ophiogomphus: male

face striped across with black 18a

face uniformly pale 18b

18a upper appendages (top view) bowed, separated by a U-shaped space, ends blunt, lower appendagesnearly as long as upper; greenish with black- brown markings 20Jun-5Sep

Ophiogomphus colubrinus

upper appendages triangular with straight edges, separated by a V-shaped space, ends pointed, lower

appendages shorter than upper; greenish with clear black markings 20Jun-2Aug

O.anomalus

18b black legs 18c

legs with extensor surfaces yellow; greenish with brown markings 20Jun-28Aug O.rupinsulensis

18c lower appendages much shorter than upper and not projecting out to sides beyond them; greenish,

brown markings on thorax 15Jun-11Aug

O.aspersus

lower appendages little if any shorter than upper and projecting sideways beyond them; yellowishgreen with brown markings 4Jun-7Jul

O.mainensis

19 female

face striped across with black 19a

face uniformly pale 19b

19a thorax without a dark central stripe; occiput without spines but with a definite fringe of hairs, horns

behind occiput stout

O.colubrinus

thorax with dark central stripe; occiput with a pair of black spines, hair not in fringe, horns behind

occiput very small

O.anomalus

19b horns behind occiput stout and conspicuous O.rupinsulensis

horns absent or small 19c

19c segments 8-9 without yellow spots; with a pair of high contiguous occipital spines O.mainensis

segments 8 and 9 each with a yellow spot; occipital spines if present small and well separated O.aspersus

20 Gomphus:

face entirely yellow-green or olive 20a

face partly or entirely dark 20g

20a legs yellow on outside 20b

legs entirely black or brown 20c

20b male: upper appendages without spine under, female: occiput with slightly convex margin fringed Gomphus lividus
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sparsely with hair, vulva less than 1/6th as long as segment 9 with lobes widely separated; dull

brown and green 14Jun-10Jul

male: upper appendages with obtuse protrusion under, female: occiput slightly bilobed; dull yellow

with pale brown thorax stripes 8Jun-12Aug

G.exilis

male: upper appendages with spine under, female: occiput with a central prominence and slight

emargination on each side; dull greenish brown 24May-14Jul

G.spicatus


20c occiput half height of eye, shape as G.lividus, fringed with long black hair, male: upper appendages'

ends convergent, slender and not meeting in middle, female: vulva about 1/3 as long as segment 9,

triangular with a short narrow cleft, no horns on vertex; greenish with black markings 1Jun-17Aug

Arigomphus furcifer

occiput height of eye, notched in middle, no hair protruding, male: these ends meeting in middle,

female: vulva as G.furcifer; yellowish green with brown and black markings 6Jun-27Jul

A.cornutus

male: upper and lower appendages' ends parallel, directed rearward, female: vulva less than 1/4 as

long as segment 9, angle between the lobes obtuse

20d

20d segments 7-9 only slightly enlarged, the greatest width less than twice the least width, 8 and 9 with

scarcely any rim, edge of 8 straight in profile, 10 half as long as 9

20e

segments 7-9 greatly enlarged, the greatest width more than twice the least width, 8 and 9 with wide

rim, edge of 8 convex in profile, 10 1/3 as long as 9 or less

20f

20e male: front hamules almost as long as rear, ending in a long slender hook, female: vulva less than 1/2

as long as segment 9, about as wide as long, not tapering to end; clear brown green and yellow 4Jun-

30Jul

Gomphus descriptus

male: front hamules much shorter than rear, rounded at end, female: vulva more than 1/2 as long assegment 9, much narrower than long, tapering to end; brown green and yellow, very hairy 26May-

22Jul

G.borealis

20f front diameter of segments 8 and 9 about equal, 8 with a single triangular yellow spot on top, occiput

of female with a small central hump; pale, hairy, wasp waist 1Jun-23Jul

G.fraternus

diameter of segment 8 much greater than 9, 8 with two spots on top, occiput of female without

hump; green with bright brown markings, abdomen blackish, wasp waist 15Jun-14Jul

G.ventricosus

20g upper pale thorax stripes flowing together with collar stripe 20h

these stripes isolated 20i

20h segments 7-9 as wide as thorax, 8 & 9 with wide curved side rims, 8 more curved than 9, 10 about a

third as long as 9; thorax greenish yellow with bright brown markings, abdomen blackish with

yellow at front and back 1May-31Jul

G.vastus

segments 7-9 much narrower than thorax, rim of 9 more curved than 8, 10 more than half as long as

9; yellowish green with strong black markings 7Jun-21Jul

G.adelphus

20i abdomen not more than 1/7th longer than hind wing, male: rear hamules leaning somewhat backward 20j

abdomen 1/5 to 1/3 longer than hind wing, male: rear hamules leaning somewhat forward 20k

20j small, 32 mm abdomen 28 mm hindwing, pale yellow upper thorax stripes near middle line only

slightly divergent; darkish, late June

Stylurus amnicola

large and robust, 40 mm abdomen 34 mm hindwing, these stripes not near middle line and very

divergent; blackish with yellow bands on abdomen 25Jun-9Sep

S.scudderi

20k segments 8 & 9 about equal in length, male: rear hamules tilted only slightly forward, front edges

nearly straight; waspwaist, black and greenish yellow 7Jul-12Oct

S.notatus

segment 9 about 1/4 longer than 8, male: rear hamules tilted far forward, front edges concave; wings

shorter than abdomen, black green and yellow 30Jun-16Sep

S.spiniceps

21 Cordulegaster:

single row of yellow abdominal spots on top; July Cordulegaster obliquapaired abdominal spots large, triangular and widely separated and eyes separated by a small space on

males, usually on females; female ovipositor barely longer than segments 9+10, 28May-14Jul

C.diastatops

paired spots small, narrowly separated or confluent, rounded behind on males usually on females,

eyes meet at point; female ovipositor 2x length of segments 9+10, 29May-14Jul

C.maculata


22 Libelluloidea:

hind wing triangle about half as far from arculus as in forewing, anal loop about as long as wide, its

included cells not in 2 long rows, undeveloped radial and medial planates

Macromiidae 23

hind wing triangle at or very close to arculus, anal loop somewhat foot shaped, divided lengthwise

by a midrib into 2 rows of cells

22a

22a forewing triangle 1 times as high as wide, anal loop with little if any development of toe, males: Corduliidae 29
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19/21

well developed anal triangle

forewing tringle 2x as high as wide, anal loop with well developed toe (except Nannothemis rearwing), male: no anal triangle

Libellulidae 24

23 Macromiidae:

occiput and vertex pale; nodus of forewing about equally distant from stigma and wing base 23May-

30Jul

Didymops transversa

occiput and vertex black; nodus of forewing clearly closer to stigma than to wing base 15Jun-28Aug Macromia illinoiensis

24 Libellulidae:

forewing triangle with front side broken making a quadrangle of it; anal loop of hind wing open

rearward, smallest dragonfly here (wing 20 mm) 20Jun-9Aug

Nannothemis bella

triple-length vacant space under stigma; (Lanark 11Jun-30Sep) Pachydiplax longipennis

vein M2 distinctly waved 24a

vein M2 smoothly curved 24b

24a wings with several bridge crossveins Libellula 26

single bridge crossvein, large brown spot on rear base of hind wing; 13Jul-10Sep Pantala hymenea

single bridge crossvein, no such spot; 11Jun-27Aug P.flavescens

24b brilliant three-colour wings: clear, yellow, brown Celithemis 25

wings almost clear 24c

24c vein Cu1 in hind wing arising from hind end of triangle Sympetrum 28

arising from outer side, sometimes only by vein width 24d

24d forewing triangle inner side less than twice as long as front side, stigma short and thick, face bone

white (if not check Sympetrum 28)

Leucorrhinia 27

inner side more than twice as long as front, stigma about 3 times as long as wide, face greenish with

brown hairs; radial planate subtends 1 row of cells (if 2 rows, it's Pantala flavescens 24a), mostly

greenish to grey-blue, brown spots in segments 3-9 19Jun-5Sep

Erythemis simplicicollis

25 Celithemis: brilliant yellow and brown spots covering half or more of wings

4 spots per wing, end one beyond stigma; 18Jun-23Aug C.elisa

5 spots per wing, end one inside stigma 15Jun-16Aug C.eponina

26 Libellula: stout body shorter than wing span, medium size, hunch-backed appearance both at rest and

in flight

wing clear (may be smoky at tip); forewing triangle 3-celled, eye seam longer than occiput, longer

and slimmer than L.julia; 21Jun-14Aug

L.incesta

wings clear except for small dark basal spots; forewing triangle 2-celled, eye seam shorter than

occiput; 7Jun-30Jul[I am not certain that the wing basal spot can be used to separate julia from incesta - a few females in

the national collection have basal spots, eye seam shorter than occiput, but 3-celled triangles.]

L.julia

basal third of both wings covered full width by blackish band, tips clear; 26Jun-30Aug L.luctuosa

nodus wing band at rear wider than 1/5 hindwing length, no spot at stigma, 28May-25Aug male L.lydia

large clear separate basal, nodal and wing-end spots, forewing basal colour does not extend into

topmost cell of triangle, female

female L.lydia


as female L.lydia, but forewing basal colour extends into topmost cell of triangle making a notch in

its rear; normally longer wingspan than lydia, males have prunescent spots on wings with age; 1Jun-

28Sep

L.pulchella

hind wing with triangular yellow to brown spot at base with white crossveins and dark rear border,

small clear brown spot at nodus; usually yellow costal streak, sometimes swarms 7May-28Aug

L.quadrimaculata

27 Leucorrhinia: white face on black head; small, not stout, wings mostly clear

all blackish except for prunescence; trigonal interspace of forewing with two rows of cells inner

third (other L. have 3 rows); 30May-21Aug

L.frigida

'blood'-red flush on thorax (only when alive) especially around wing roots, usually on sides of

segments 1-2 as well, otherwise black abdomen; prunescence can form a row of spots on top of

abdomen of pattern similar to the yellow spots of L.hudsonica; 31May-19Aug[Many publications use a 2-cell width of the radial planate to key this species. It is inapplicable here;

several local populations have 1-cell planates.]

L.glacialis

with line of broad oval yellow spots on top of segments 1-6 (reddish on some males), usually

yellow is visible at the bottom of segments 1-2 even through prunescence; a bit stouter than other L.,

thorax may show a bit of red; 9Jun-30Aug

L.hudsonica
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20/21

clear yellow or reddish spot on top of segment 7 much larger and brighter than anything on other

segments; 19May-26Aug

L.intacta

white ring, or at least a lot of white, at junction of thorax and abdomen; a bit larger than other L.,

thorax with no red, the white can be largely obscured by prunescence; 1Jun-10Aug

L.proxima

segments 1-3 with line of narrow linear yellow streaks on top (may be faint); check of appendage

shapes required to be sure (Renfrew 20Jun-7Aug)

L.patricia

28 Sympetrum: hybridise often, so expect intermediate forms

male: upper abdominal appendages with prominent tooth on bottom; female: subgenital plate deeply

cleft

28a

male: these appendages only finely toothed; female: plate with tiny tooth or none 28c28a wing veins reddish, overall brownish red; male: hamuli forked for about 1/4 visible length, rear

branch 4 times as stout as inner, face cherry red with clear black line bottom quarter of lower lip;21Jun-18Sep

Sympetrum internum

wing veins not reddish, little or no black on lower lip or lower edge of black indistinct 28b

28b reddish throughout, pale stripes on thorax; male: hamuli forked for about 1/3 visible length, rear

branch barely twice as stout as inner, female: subgenital plate tips upturned against rear of segment

9, face yellowish red 13Jun-24Sep

S.rubicundulum

abdomen with black side triangles, usually linked into a line with triangle-jagged top; initially

yellow-brown turning red with age, male: hamuli forked for less than 1/4 its visible length, rear

branch 2-3 times as stout as inner, frons white upper lip yellow-white, female: face greenish white20Jun- 29Oct

S.obtrusum

28c wings tinged with dark yellow over basal half, larger area and darker on hindwings; brown, smallpale yellow spots behind head 1Jul-1Oct S.semicinctum

wings clear, yellow only on costal strip or at extreme base 28d

28d legs black; only Sympetrum with no red anywhere on male, only black and yellow 3Jul-26Sep S.danae

legs more or less yellow 18e

28e legs entirely yellow; yellow when young all red when mature, slender, thin legs 24Jul-3Nov S.vicinum

legs striped with black on sides; brownish red, wings with yellow veins at tips 14Jul-14Sep S.costiferum

29 Corduliidae:

M4 and Cu1 in forewing parallel to divergent 29a

these veins convergent at wing margin 29b

29a forewing triangle 3 cells, wings >30 mm; brownish, no visible spots or stripes, flies only briefly after

dusk 7Jun-30Jul

Neurocordulia

yamaskanensis

triangles and subtriangles each of a single cell, tiny (24 mm); black with reddish lower lip and paleyellow spot on thorax 19May-11June Williamsonia fletcheri

29b wings with blotchy smoky brown spots at base, nodus and end; hindwing triangle 2-celled, large,brown hairy thorax 7Jun- 20Aug

Epicordulia (Epitheca)princeps

no such spots 29c

29c hindwings with opaque brown spots at base; brownish, face yellowish 25May-7Jul Helocordulia uhleri


hind wing with 2 cubito-anal crossveins Somatochlora 31

with 1 such crossvein 29d

29d black abdomen 2x(male) to 3x(female) as wide at end as at waist; male with white abdominal ring

segment 2 and sometimes 3, green eyes; female yellow-brown segments 1 and 2, brown eyes;

18May-21Jul

Dorocordulia libera

metallic green with green eyes, abdomen only twice as wide at widest point as at narrowest 24May-

8Aug

Cordulia shurtleffi

brown

30 Epitheca (Tetragoneuria):

T-spot on frons clearly defined; male: upper appendages each with small sharp spine projectingdownward at about 2/5th of its length 8May-10Jul

E.spinigera

T-spot indistinct or incomplete (usually base only) 30a

30a male: upper appendages with outer tip bent downward, with a bump on upper side where slope

begins, no crossbar on frons T-spot, female: vulva ends cylindrical extending to margin of segment

9; stocky 6May-18Jul

E.canis

large triangular basal spot rear wings only, row of yellow spots each side of abdomen; male: without

such a bump, female: ends conical extending well beyond margin of segment 9; hairy thorax 5Jun-

E.cynosura
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21/21

18Jul

31 Somatochlora:

upper lip yellowish, often with black band across front border, face below suture mostly yellow;

brilliant bronze and green thorax, male: scythe-shaped appendages 1Jul-9Sep

Somatochlora tenebrosa

upper lip black, if partly yellow with no such black band 31a

31a middle segments with clear rings of white about 1/10th their length; one pale stripe/spot on side of

metallic green thorax

31b

no such white rings 31c

31b thorax stripe barely distinguishable; male: lower appendage squared off, nearly parallel to its widely

forking tip, female: appendages viewed from side straightish below, much more convex on uppermargin (Tremblant 24Jun-4Sep)

S.cingulata

yellow elongate spot each side of thorax; male: lower appendage elongate-triangular, stronglytapering to single upturned tip, female: appendages about equally convex on upper and lower

margins, 26Jun-1Sep

S.albicincta

31c two side stripes on thorax 31d

only one such stripe; face blackish green with 3 yellow spots, thorax metallic green with brown-

violet markings 23May- 29Aug

S.franklini

31d each thorax stripe represented by round spot; face blackish blue 6Jun-30Aug S.minor

these spots elongated 31e

31e first thorax stripe narrower and much longer than 2nd; face brownish yellow with black markings on

frons, lower lip black 18Jun-1Sep

S.walshi

this stripe shorter, about 1/2 thorax height, usually narrower than 2nd 31f31f both thorax stripes bright yellow and sharply defined 31g

these stripes dull yellow and ill-defined 31h

31g middle segments with pale spots at front bases; brown with metallic sheen 27May-27Aug S.forcipata

these segments with no pale spots; yellowish face, barely visible yellow bars on metallic green

thorax with light brown hairs (Tremblant 8Jun-30Aug)

S.elongata

31h male: upper appendages very hairy, tips recurved, female: subgenital plate triangular in profile, taper

pointed and erect; dark with patches of dark yellow, hairy thorax (Tremblant 21Jun-15Sep)

S.williamsoni

male: upper appendages not hairy, not recurved at tips, lower curved upwards, female: subgenital

plate broadly triangular, not erect; blackish face with some pale yellow, hairy thorax 5Jun-11Jul

S.kennedyi

male: upper appendages not hairy, not recurved at tips, lower not curved upwards, female: subgenital

plate cylindrical; segment 2 with single small pale spot each side, little thorax hair (19Jul-30Aug)

S.incurvata

illustrations for 30-31main page
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A Guide to the Adult Damselflies

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